Machine for sharpening rotary cylindrical cutters



April 29, 1941. M Q MCCQRMAcK 42,239,683

ma Fon smmrnxme ROTARY cYLmnnrcAn. curTERs Filed Feb. 7. 1940. shaw-sheet 1 WEE.

April 29, 1941. M. c. MCCORMACK 2,239,633

MACHINE Fon SHARPENING ROTARY CYLINDRIcAL cU'rT'ERs Filed Feb. 7, 1940 2 Shaets-Sheet Patented Apr. 29, 1941 MACHINE FOR SHARPENIN G ROTARY CYLINDRICAL CUTTERS Marie C. McCormack, New Orleans, La.

Application February 7, 1940, Serial No. 317,744

8 Claims.

This invention relates to a sharpener for rotary or cylindrical cutrters or knives such as, for example, the knives used in pencil Sharpeners, cylindrical reamers, cutting tools, and the like having axially or spirally extending blades about a cylindrical body portion. Knives of this type are ofttimes arranged to operate in pairs, and it is important that both knives or cutters of each pair have the same overall diameter and uniform cutting edges.

An object of fthe invention is to provide a sharpening device or apparatus for cutters or knives of the type speciiied which will permit a rapid or relatively quick sharpening operation and which at the same time will result in a uniforni cutting edge throughout the length of the bl-ades of the cutter to be sharpened'.

Another object is to provide a sharpening apparatus for cylindrically arranged knives or blades whereby the latter may be expeditiously sharpened in pairs with Ithe blades of bothpairs sharpened uniformly throughout their lengths.

Generally stated, the invention contemplates a Sharpener for knives or blades of the type specified wherein a pair of coacting sharpening abrasives orhones are yieldingly urged against the blades or knives 'to be sharpened at diametrically opposite points and under equal and uniform pressure, means being provided whereby the hones may be reciprocated longitudinally or axially of the blades during the sharpening operation.

Further and additional objects include the provision of sharpening apparatus for blades of the type specified which is simple in construction and rapid yet accurate in its sharpening operation,

is capable of accommodating knives or cutters in pairs and of varying lengths, is relatively low in cost of manufacture, and embodies relatively few parts which are easily replaceable and will give long and efficient service.

The foregoing and other objects and advantages will become apparent in view of the following description taken in conjunction with the drawings, wherein:

Fig. 1 is a View in end elevation of a Sharpener for rotary or cylindrical knives constructed in accordance with the features of the present invention:

Fig. 2 is a top plan view of Fig. 1;

Fig. 3 is a view in side elevation; and

Figs. 4 and 5 are 'sectional views taken substantially on the lines 4-4 .and 5-5, respectively, of Fig. 3.

Referring to the drawings in detail, the reference character I0 generally indicates the frame of the machine which may be in the form of a casting having a base II)a and an upright portion I 0b, the opposite edges of the base having projecting therethrough screw bolts II by means of which the machine may be anchored to a suitable support.

yThe frame or casting I0, as shown herein is formed with a pair of bearing bosses I2 and I3, each of which has a bearing therein through which knife holding shafts I4 and I5 project. These shafts I4 and I5 are provided with blade mounting portions I4ab and I5a which in the present instance are shown as threaded to receive the cylindrical blades or knives to be sharpened, a

pair of which are indicated at B and B in 2. 'I'he blades or knives to rbe sharpened in this instance are those used in a pencil Sharpener and which have their interior bores threaded. The shafts I4 and I5 are provided with stop shoulders or thrust bearing portions I4b and I5", which obviously may be separate nuts or bearing co1- lars instead of being formed integrally with thel shaft.

'Ihe outer ends of shafts I4 and I5 have secured thereon pulleys I6 and Il lwhich are driven from a pulley wheel I8 mounted on a stub shaft I9, the latter being mounted in a bearing boss 20. The pulley wheel I8 has trained thereover a belt 2| whichl is also trained over the pulleys I6 and I'I so that when the wheel I8 is rotated, the shafts I4 and I5 are in turn rotated.

simultaneously and in the same direction. Wheel I 8 may be power operated but is here shown provided with a handle 22 for manual operation. A pair of abrasive devices or hones are indicated at 23 and 24, said hones each bein-g mounted in holders 25 and 26 of similar construction which at their undersdes are formed with dovetail guides 25a and 26a which engage in slideways orgroovesk 27 and 28 formed in a carrying or supporting block 29. Block 29 is mounted for sliding movement with respect to the shafts I4 and I5, and with this in viewit has a dovetail shaped rib 30 formed on the underside thereof which engages in a like shaped groove or slideway 3| formed in the base Illa of the casting I 0. v'I 'he rib 30 is extended rearwardly of the block 29 so that when the block is in fully retracted position, the rear end of the rib 30 contacts the rear upstanding wall lob of the Ill, note Fig. 4. At the front of the block, the" rib terminates flush with the adjacent end wall of the block. The underside of the block 29 is provided with ribs 29a which project laterally on opposite sides of the rib 30 in line with the grooves 21 and 28 and strengthen the block in the region of said grooves. These ribs 29a slide on the base Il!a and also steady the block 2S.

It will thus be seen that the hone or abrasive holders 25 and 25 are mounted for independent sliding movement towards and from the knives or cutters B and B', while at the same time they may be moved or reciprocated as a unit axially of said knives or cutters. To ensure an equal application of sharpening pressure of the hones with respect to the knives, a spring 33 is connected to the holders 25 and 26 and at its opposite ends is anchored to screws 34 and 35 which project through said holders and are adapted to engage the hones and hold them in proper position with respect to the cutters or knives B, B to be sharpened.

The cutters or knives B and B may be maintained in position on the chuck portions I4a and I5a of the shafts AIll and I5 by means of wing nuts 35, as clearly shown in Fig 2.

'Io operate the machine, the cylindrical knives or cutters to be sharpened are inserted on the chuck portions I4a and I5a of the shafts I4 and I5, and the wing nuts 36 then tightened down to hold the knives securely in sharpening position. Although the chuck portions I4a and I5a of the shafts I4 and I5 are shown threaded, it will be understood that they could be formed smooth if desired to accommodate cylindrical cutters having smooth bores or even threaded bores. When inserting the knives to be sharpened, the spring 33 may beV removed, or else the hones may be retracted just sufficiently to clear the knives or cutters and then released. The drive wheel I8 is then rotated, causing the cutters to revolve rapidly in contact with the hones until the sharpening operation is completed. The ratio of the pulley Wheel IG with respect to the pulleys I6 and I1 is preferably such as to result in a relatively high speed of rotation of the shafts I4 and i5. Since the spring 33 exerts an equal tension on the hones 23 and 24 and since the latter are mounted for sliding movement in their respective supports, the sharpening pressure of both hones on the blades of the knives B and B will be equal and will result in a uniform sharpening operation with respect to both knives or cutters.

In the event the knives or cutters to be sharpened are of a length greater than the width of the sharpening edges of the hones 23 and 24, then the hones may be reciprocated axially of the shafts I4 and I5 during the sharpening operation, the pressure still remaining uniform with respect to both knives.

Whenever it is desired to remove the hones 23 and 24, it is only necessary to retract the screws 34 and 35 and release the spring 33, whereupon the hones may be readily removed from their holders 25. y

The parts of the Sharpener are relatively few in number, simple in construction, yet withall a highly efficient sharpening action and uniform with respect to both cutters of each pair is assured. v

It will be understood that certain changes in construction and design may be adopted without departing from the spirit or scope of the invention as dened by the appended claims.

What i-s claimed is:

1. In a machine for sharpening rotary or cylindrical knives or cutters, a frame, a pair of spindles mounted in substantially axial parallel relation for rotation in said frame and having aasaoss portions constituting chucks on which the knives or cutters to be sharpened may be mounted, a pair of abrasives or hones slidably mounted in spaced relation substantially perpendicularly to and on opposite sides of the axes of said chucks, a spring common to both abrasives or hones normally urging the latter uniformly against the cutters or knives to be sharpened, and means for rotating said spindles.

2. In a machine for sharpening rotary or cylindrical knives or cutters, a frame, a pair of spindles or shafts mounted in substantially axially parallel relation for rotation in said frame, said spindles having portions constituting chucks on which the knives or cutters to be sharpened may be mounted, a pair of sharpening hones, holders for said hones slidably mounted on opposite sides of and in a plane substantially perpendicular to the axes of said chucks, a spring connecting at opposite ends to said holders yieldingly urging the latter together with the hones towards the knives or cutters to be sharpened, means supporting said holders together with said hones bodily as a unit, said latter means being mounted for sliding movement in said frame in an axial direction with respect to said chucks, and means for rotating said spindles.

3.k In a machine for sharpening rotary or cylindrical knives or cutters, a frame, a pair of spindles mounted in substantially axially parallel relation for rotation in said frame, said spindles having portions projecting outwardly and constituting chucks on which the knives or cutters to be sharpened may be mounted, a pair of sharpening hones, holders for said hones slidably mounted on opposite sides of and in a plane substantially perpendicular to the axes of said chucks, means resiliently urging said holders together with the hones towards the knives or cutters to be sharpened, ymeans supporting said holders together with said hones as a unit, means mounting said supporting means for sliding movement in an axial direction with respect to said chucks and whereby the hones may be moved axially of the knives or cutters to be sharpened, and means for rotating said spindles.

4. InV a machine for sharpening rotary or cylindrical knives or cutters, a frame, a pair of spindles mounted in substantially axially parallel relation for rotation in said frame, said spindles having portions projecting outwardly and constituting chucks on which the knives or cutters to be sharpened may be mounted, a pair of sharpeninghones, holders for said hones mounted Vfor sliding movement in a direction substantially perpendicular tothe axes of said chucks, a. spring connectedI at opposite ends, respectively, to said holders and whereby the hones are yieldingly urged against the knives or cutters to be sharpened uniformly and equally throughout the vsharpening operation, a frame block in which said holders arev slidingly mounted, said frame block being also slidingly mounted but in a direction axially of said chucks and whereby the hones may be reciprocated along the length of the knife or cutter to be sharpened, and means for rotating said spindles.

5. In a machine for sharpening rotary or cylindrical knives or cutters, a frame, a pair of spindles mounted in substantially axially parallel relation for rotation in said frame, said spindles having projecting portions constituting chucks on which the knives or cutters to besharpened may be mounted, a pair of sharpening hones, holders for said hones mounted for sliding movement in a plane perpendicular to the axes of said chucks and whereby the holders together with the hones may be moved toward and away from the knives or cutters to be sharpened, a spring connected at opposite ends, respectively, to said holders and whereby the hones are yieldingly urged with uniform pressure against the knives or cutters to be sharpened, a frame'block being mounted in a guideway extending axially with respect to sai-d chucks and spindles, and means for simultaneously rotating said spindles.

6. In a machine for sharpening rotary or cylindrical knives or cutters of the type having an axial bore therethrough, a frame, a pair of spindles mounted in substantially axially parallel relation for rotation in said frame, said spindles having projecting portions on which the knives or cutters to be sharpened may be mounted, a pair of sharpening hones, holders for said hones, a frame block having guideways therein extending in a plane at substantially right angles to the axes of said spindles, said holders being sli'dably mounted in said guideways, a spring connected at opposite ends, respectively, to said holders and yieldingly urging the latter towards thespindles, said frame block being mounted in a guideway formed in said frame, said guideway extending in a direction substantially parallel to the axes of said spindles, and whereby the hones may be movedbodily as a unit along the full length of the knife or cutter to be sharpened, and means for simultaneously rotating said spindles.

7. In a machine for sharpening rotary or cylindrical knives or cutters, a frame, a pair of chuck members rotatably mounted in said frame and adapted to support the knives or cutters to be sharpened in substantially axial parallel relation, sharpening abrasives or hones disposed in spaced relation on opposite sides of the axes of said chuck members and mounted for movement substantially perpendicularly to the knives or cutters, spring means urging said abrasives or hones uniformly against the knives or cutters, and means for rotating said chuck members.

8. In a machine for sharpening rotary or cylindrical knives or cutters, a frame, a pair of spindles mounted in substantially axial parallel relation for rotation in said frame and adapted to support the knives or cutters to be sharpened, a pair of abrasives or hones movably mounted in spaced relation substantially perpendicularly to and on opposite sides of the axes of said spindles, spring means common to both abrasives or hones normally urging the latter uniformly against the cutters or knives to be sharpened, and means for rotating said spindles.

MARIE c. MCCORMACK. 

